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Boletus edulis loaded with gamma-Fe2O3 nanoparticles as a magnetic sorbent for preconcentration of Co(II) and Sn(II) prior to their determination by ICP-OES
(SPRINGER WIEN, 2018) Özdemir, Sadin; Yalçın, M. Serkan; Kılınç, Ersin; Soylak, Mustafa
The authors show that the fungus Boletus edulis loaded with gamma-Fe2O3 nanoparticles is a viable sorbent for magnetic solid phase extraction of trace levels of Co(II) and Sn(II). The surface structure of immobilized magnetized B. edulis was characterized by FT-IR, SEM and EDX. Experimental parameters were optimized. Following elution with 1 M HCl, the ions were quantified by ICP-OES. The limits of detection are 21 pg.mL(-1) for Co(II), and 19 pg.mL(-1) for Sn(II). The preconcentration factors are 100 for both ions. The sorption capacities of the sorbent are 35.8 mg.g(-1) for Co(II) and 29.6 mg.g(-1) for Sn(II). The method was applied to the analysis of certificated reference materials and gave >= 95% recoveries with low RSDs. It was also successfully applied to the quantification of Co(II) and Sn(II) in spiked environmental and food samples.
Competitive adsorption of VOCs (benzene, xylene and ethylbenzene) with Fe3O4@SiO2-NH@BENZOPHENONE magnetic nanoadsorbents
(Elsevier, 2023) Ece, Mehmet Şakir; Ece, Mehmet Şakir
Volatile organic compounds (VOCs), which are toxic, mutagenic and carcinogenic, are considered a critical factor for air pollution and cause serious harm to the eco-environment and human health. In this study, Fe3O4, Fe3O4@SiO2-NH2, Fe3O4@SiO2-NH@BENZOFENONE were synthesized as new magnetic nanoadsorbents (MNAs) and used for the first time in the removal of gas-phase benzene, xylene and ethylbenzene. The synthesised MNAs were characterized by SEM-EDS, TEM, FTIR, XRD, VSM, TGA and BET analyses. The characterization results showed that the MNAs have mesoporous structure, type IV physioresorption and type H3 hysteresis loop character. In order to clarify the comparative and competitive adsorption behaviour, the adsorption capacity of Fe3O4@SiO2-NH@BENZOFENONE MNA was found to be in the order of xylene > ethylbenzene > benzene in both single, binary and ternary component systems. The adsorption kinetics of benzene, xylene and ethylbenzene with Fe3O4@SiO2-NH@BENZOFENONE MNA were found to be governed by multistep mechanisms. Fe3O4@SiO2-NH@BENZOFENONE MNA showed reuse efficiencies of 83.07%, 84.35% and 82.99% after 5 cycles for benzene, xylene and ethylbenzene respectively. In the framework of the results, Fe3O4@SiO2-NH@BENZOPHENONE MNA, which has a high potential in terms of both adsorption capacity and reuse efficiency, is proposed as a promising adsorbent for the efficient removal of benzene, xylene and ethylbenzene. © 2023 Elsevier B.V.
Fullerene C-60 functionalized gamma-Fe2O3 magnetic nanoparticle: Synthesis, characterization, and biomedical applications
(TAYLOR & FRANCIS LTD, 2016) Kilinc, Ersin
Hybrid magnetic nanoparticles composed from C-60 fullerene and -Fe2O3 were synthesized by hydrothermal method. XRD, FT-IR, VSM, SEM, and HR-TEM were employed for characterizations. The magnetic saturation value of C-60--Fe2O3 magnetic nanoparticles was 66.5 emu g(- 1). Concentration of Fe in nanoparticles asdetermined by ICP-OES was 40.7% Fe. Particle size of C-60--Fe2O3 magnetic nanoparticles was smaller than 10 nm. Maximum adsorption capacity of C-60--Fe2O3 for flurbiprofen, a non-steroidal anti-inflammatory drug, was calculated from Langmuir isotherm as 142.9 mg g(- 1).
gamma-Fe2O3 magnetic nanoparticle functionalized with carboxylated multi walled carbon nanotube for magnetic solid phase extractions and determinations of Sudan dyes and Para Red in food samples
(ELSEVIER SCI LTD, 2018) Kilinc, Ersin; Celik, Kadir Serdar; Bilgetekin, Havin
Hybrid nanostructures composed of gamma-Fe2O3 (maghemite) and carboxylated-multi walled carbon nanotube (cMWCNT) were used for the magnetic solid phase extractions and determination of Sudan I, II, III, IV, Para Red, Sudan Black B and Sudan Red 7B in chili products. High performance liquid chromatography (HPLC) was employed for the measurements. Limit of quantification (LOQ) values were found in the range 0.44-2.82 ng mL(-1) for analytes. The best extraction parameters were determined as pH 8.0, 40 mg of magnetic nanoparticle, 4.0 min of contact time, 0.3 mL desorption by acetonitrile. The samples were dissolved in acetone-dichloromethane-methanol (3: 2: 1, v/v/v) and diluted with acetonitrile-methanol (v/v; 80: 20) before the method was applied. Concentrations of Sudan dyes and Para Red were determined in four samples of chili powder from less than LOQ to 31.21 +/- 1.6 ng g(-1), two samples of chili tomato sauces (lower than LOQ) and two samples of ketchup (lower than LOQ).
Hepato-preventive and anti-apoptotic role of boric acid against liver injury induced by cyclophosphamide
(Elsevier GmbH, 2019) Çetik Yıldız, Songül; Demir, Cemil; Demir, Cemil; Kulcanay Şahin, İlknur; Teksoy, Özgün; Ayhancı, Adnan
This study aims to examine cyclophosphamide (CP) exsposure associated toxicity on rat livers and the likely defensive effects of boric acid (BA). The rats used in this study were divided into four groups: control group, CP group, BA group, and BA + CP group. The present study was carried out using routine histological H&E stain, immunohistochemical stain caspase-3 as apoptotic marker, serum biochemical analysis for liver function markers (alanine transaminase (ALT), aspartate transaminase (AST) and alkalen phosphatase (ALP)), oxidative stress markers (total oxidant status (TOS), oxidative stress index (OSI) and total antioxidant capacity marker (TAC)). In the CP group, the levels of ALT, AST, ALP, TOS, OSI and caspase-3 increased whereas TAC levels decreased compared with the control group. In the BA + CP group, the levels of ALT, AST, ALP, TOS, OSI and caspase-3 decreased whereas TAC levels increased compared with the CP group. The histopathological evaluation of light microscope images and immunohistochemical caspase-3 activity in the BA + CP group were found to be decrease compared with those in the CP group. In conclusion, BA was successful in defending the liver against apoptosis and histopathological changes that are attributable to CP. © 2019 Elsevier GmbH
Highly improved solar cell efficiency of Mn-doped amine groups-functionalized magnetic Fe3O4@SiO2 nanomaterial
(Wiley Online Library, 2021) Kutluay, Sinan; Horoz, Sabit; Şahin, Ömer; Ekinci, Arzu
Herein, magnetic Fe3O4@SiO2 nanomaterial functionalized with amine groups (Fe3O4@SiO2@IPA) doped with manganese (Mn) was prepared, characterized and used for solar cell application. Fe3O4@SiO2@IPA-Mn was prepared via the co-precipitation and sol-gel techniques. Energy-dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements were performed to examine the structure of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@IPA and Fe3O4@SiO2@IPA-Mn. General morphology and textural properties of the prepared magnetic nanomaterials were clarified by Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). In addition, Ultraviolet-visible (UV-Vis) spectroscopy and thermal gravimetric analysis (TGA) were used to have a knowledge about the energy band gap and thermal behavior of the prepared magnetic nanomaterials. The energy band gap of Fe3O4@SiO2@IPA with spinel structure was determined as approximately 2.48 eV. It was understood that Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@IPA showed type IV-H3 hysteresis cycle according to IUPAC. From the BET data, it was determined that the specific surface areas of Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@IPA were 60.85, 28.99 and 40.41 m(2)/g, respectively. The pore size distributions of Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@IPA were calculated as 8.55, 1.53 and 1.70 nm, respectively, by the BJH method. Also, it was observed that the dominant pore widths of Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@IPA were calculated similar to 5.58, similar to 0.88 and similar to 17.92 nm, respectively, by the DFT method. Au/CuO/Fe3O4@SiO2@IPA-Mn/ZnO/SnO2: F solar cell device was created using existing Fe3O4@SiO2@IPA-Mn as a buffer layer. The power conversion efficiency (%) of Fe3O4@SiO2@IPA-Mn based solar cell device was calculated as 2.054. This finding suggest that Fe3O4@SiO2@IPA-Mn can be used as a promising sensitizer in solar cell technology. Moreover, in this study, the effectiveness of the modification of manganese (one of the transition metals, which is cheap and easily available) with magnetic nanomaterials in the use of solar cell technology was demonstrated for the first time.
Investigation of the antibiotic resistance and biofilm-forming ability of Staphylococcus aureus from subclinical bovine mastitis cases
(ELSEVIER SCIENCE INC, 2016) Demir, Cemil; Demir, Cemil
A total of 112 Staphylococcus aureus isolates obtained from subclinical bovine mastitis cases were examined for antibiotic susceptibility and biofilm-forming ability as well as genes responsible for antibiotic resistance, biofilm-forming ability, and adhesin. Antimicrobial susceptibility of the isolates were determined by disk diffusion method. Biofilm forming ability of the isolates were investigated by Congo red agar method, standard tube method, and microplate method. The genes responsible for antibiotic resistance, biofilm-forming ability, and adhesion were examined by PCR. Five isolates (4.5%) were identified as methicillin-resistant Staph. aureus by antibiotic susceptibility testing and confirmed by mecA detection. The resistance rates to penicillin, ampicillin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, enrofloxacin, and amoxicillin-clavulanic acid were 45.5, 39.3, 33, 26.8, 5.4, 0.9, and 0.9%, respectively. All isolates were susceptible against vancomycin and gentamicin. The blaZ (100%), tetK (67.6%), and ermA (70%) genes were the most common antibiotic-resistance genes. Using Congo red agar, microplate, and standard tube methods, 70.5, 67, and 62.5% of the isolates were found to be biofilm producers, respectively. The percentage rate of icaA, icaD, and bap genes in Staph. aureus isolates were 86.6, 86.6, and 13.4%, respectively. The adhesion molecules fnbA, can, and clfA were detected in 87 (77.7%), 98 (87.5%), and 75 (70%) isolates, respectively. The results indicated that Staph. aureus from sublinical bovine mastitis cases were mainly resistant to beta-lactams and, to a lesser extent, to tetracycline and erythromycin. Also, biofilm- and adhesion-related genes, which are increasingly accepted as an important virulence factor in the pathogenesis of Staph. aureus infections, were detected at a high rate.
Magnetic solid phase extractions of Co(II) and Hg(II) by using magnetized C-micaceus from water and food samples
(ELSEVIER SCI LTD, 2019) Ozdemir, Sadin; Mohamedsaid, Siham Abdullah; Kilinc, Ersin; Soylak, Mustafa
A new bio-MSPE sorbent based on the use of C. micaceus and gamma-Fe2O3 magnetic nanoparticle was prepared for the preconcentrations of Co(II) and Hg(II). Critical parameters including pH, flow rate, quantity of C. micaceus, quantity of gamma-Fe2O3 magnetic nanoparticle, eluent (type, concentration and volume), sample volume, and foreign ions were examined. Surface structure and variations after interaction with Co(II) and Hg(II) of bio-MSPE sorbent were investigated by FT-IR, SEM, and EDX. The impact of bio-MSPE column reusage was also tested. The biosorption capacities were determined as 24.7 mg g(-1) and 26.2 mg g(-1), respectively for Co(II) and Hg(II). Certified reference materials were utilized to find out the accuracy of the prepared bio-MSPE method. This novel bio-MSPE method was accomplished by being applied to real food and water samples. In particular, it will be possible to make use of C. micaceus as new alternatives, in environmental biotechnology applications.
Metallo and metal free phthalocyanines bearing (4-(1(4-phenoxyphenyl)-1-phenylethyl)phenol substituents: Synthesis, characterization, aggregation behavior, electronic, antioxidant and antibacterial properties
(ELSEVIER SCIENCE SA, 2014) Agirtas, M. Salih; Guven, M. Emin; Gumus, Selcuk; Ozdemir, Sadin; Dundar, Abdurrahman
As starting material the phthalonitrile derivative bearing (4-(1(4-phenoxyphenyl)-1-phenylethyl)phenol substituents at peripheral position was prepared by a nucleophilic displacement reaction. Cyclotetramerization of 4-(4-(1-(4-hydroxyyphenyl)-1-phenylethyl)phenoxy)phthalonitrile derivative in the presence of corresponding metal salts gave the new metallophthalocyanines. Metal free phthalocyanine was obtained from the reaction of 4-(4-(1-(4-hydroxyyphenyl)-1-phenylethyl)phenoxy)phthalonitrile units. The novel compounds have been characterized by using various spectroscopic data. The aggregation investigations carried out in different concentrations indicate that 4-(4-(1-(4-hydroxyyphenyl)-1-phenylethyl)phenoxy)phthalocyanine compounds do not have any aggregation behavior for the concentration range of 10(-4)-10(-5) M in tetrahydrofuran. The antioxidant activities of novel compounds were analyzed through radical scavenging ability of 1,1-dipheny1-2-picrylhydrazyl, chelating ability to ferrous ions and reducing power. In addition to these, the antibacterial activities of compounds were investigated. Moreover, the ground-state geometries of the complexes were optimized using B3LYP/6-31G(d,p) level of density functional theory in order to predict the three-dimensional geometries and electronic structure. (C) 2014 Elsevier B.V. All rights reserved.
O-carboxymethyl chitosan Schiff base complexes as affinity ligands for immobilized metal-ion affinity chromatography of lysozyme
(ELSEVIER SCIENCE BV, 2018) Alacabey, İhsan; Baran, Talat; Erdönmez, Demet; Aksoy, Neşe Hayat; Alacabey, İhsan; Menteş, Ayfer; Odabaşı, Mehmet
We synthesized Ni2+-attached O-Carboxymethyl chitosan Schiff base complexes embedded composite cryogels (Ni2+-O-CMCS-CCs) by means of polymerization of gel-forming precursors at subzero temperatures. Prepared affinity cryogel showed excellent adsorption performance for lysozyme selected as model protein to test adsorption parameters, demonstrating an adsorption capacity of 244.6 mg/g (15.3 mg/g for Ni2+ minus O-CMCS-CCs), with fast adsorption equilibrium within 30 min and good reversibility. The performance of Ni2+-O-CMCS-CCs for lysozyme was also evaluated by SDS-PAGE, and a purification efficiency of 86.9% with 89.5% purification yield was determined. The swelling test, FT-IR, and SEM analysis were carried out for the characterization of Ni2+-O-CMCS-CCs. At the end of 35 adsorption-desorption cycles, there was no significant change in the adsorption capacity. (C) 2018 Elsevier B.V. All rights reserved.
Preconcentration of metal ions using microbacteria
(SPRINGER WIEN, 2013) Ozdemir, Sadin; Okumus, Veysi; Dundar, Abdurrahman; Kilinc, Ersin
This review (160 refs). covers the current state of the art of microbacteria-based sorbents for preconcentration of metal ions at trace levels. We highlight advantages and major challenges of the techniques and discuss future perspectives of both batch and column-based methods. Particular attention is paid to the preconcentration of metal ions using resin-immobilized microbacteria for solid phase extractions. We also discuss detection methods including UV-vis spectrophotometry, FAAS, ICP-OES and ICP-MS. Analytical figures of merit are compared, and examples are given for the application to a variety of samples including food, beverages, alloys, water, soil, and geological samples.
Preconcentrations and determinations of copper, nickel and lead in baby food samples employing Coprinus silvaticus immobilized multi-walled carbon nanotube as solid phase sorbent
(ELSEVIER SCI LTD, 2019) Ozdemir, Sadin; Kilinc, Ersin; Oner, Ebru Toksoy
Preconcentrations of Cu(II), Ni(II) and Pb(II) ions by using Coprinus silvaticus immobilized multiwalled carbon nanotube (MWCNT) were investigated. Effects of important parameters on preconcentration procedure were examined. The best pH values of for Cu(II), Ni(II) and Pb(II) were found to be 6.0, 6.0 and 4.0, respectively. Flow rate of sample solution was 2.0 mL min(-1), while desorption was achieved at 1.0 mL min(-1) flow rate. Preconcentration factors were achieved as 60 for Cu(II), Ni(II) and 70 for Pb(II) (by dividing initial sample volume to final volume). LODs were calculated as 0.014, 0.016 and 0.093 ng mL(-1), respectively for Cu(II), Ni(II) and Pb(II). Accuracy of the method was checked by applying to certified reference samples. Inductively coupled plasma optical emission spectrometer (ICP OES) was employed for measurements of Cu(II), Ni(II) and Pb(II) in digested baby food samples.
Preconcentrations of Ni(II) and Co(II) by using immobilized thermophilic Geobacillus stearothermophilus eSO-20 before ICP-OES determinations
(ELSEVIER SCI LTD, 2018) Yalcin, M. Serkan; Ozdemir, Sadin; Kilinc, Ersin
This study deals with the preconcentrations of Ni(II) and Co(II) ions in real samples using the solid phase extraction method (SPE) before their determinations by inductively coupled plasma optical emission spectrometry (ICP-OES). Thermophilic bacterium Geobacillus stearothermophilus SO-20 (Accession number: KJ095002), loaded with Amberlite XAD-4, was utilized as a novel biosorbent. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope (SEM) were employed for the investigation of the bacterial surface before and after Ni(II) and Co(II) biosorption. The experimental parameters were examined to find the best conditions. The retained Ni(II) and Co(II) ions on the biosorbent were eluted by using 5.0 ml of 1.0 mol l(-1) HCI as the best eluent. The sorption capacities were found to be 16.8 mg g(-1) for Ni(II) and 21.6 mg g(-1) for Co(II). It was also successfully used for the quantification of Ni(II) and Co(II) in a river water sample, some vegetables and soil.
Simultaneous preconcentrations of Co2+, Cr6+, Hg2+ and Pb2+ ions by Bacillus altitudinis immobilized nanodiamond prior to their determinations in food samples by ICP-OES
(ELSEVIER SCI LTD, 2017) Ozdemir, Sadin; Kilinc, Ersin; Celik, Kadir Serdar; Okumus, Veysi; Soylak, Mustafa
A novel solid phase extraction method was developed for simultaneous preconcentration-separation of Co2+, Cr6+, Hg2+ and Pb2+ ions prior to their determinations in food samples by ICP-OES. Thermophilic Bacillus altitudinis immobilized nanodiamond was used as a new biosorbent. SEM and FT-IR analysis were studied to characterize the biosorbent. The optimum pH values of quantitative biosorption for Co2+, Cr6+, Hg2+ and Pb2+ were found to be 5.0, 6.0, 6.0 and 6.0, respectively. A flow rate of 3.0 mL min(-1) was selected as optimum for all metal ions. 5 mL of 1 mol/L HCl was used as eluent. Preconcentration factor was achieved as 80. LODs were calculated as 0.071, 0.023, 0.016 and 0.034 ng mL(-1), respectively for Hg2+, Co2+, Cr6+ and Pb2+. The biosorption capacities were calculated for Co2+, Cr6+, Hg2+ and Pb2+ as 26.4, 30.4, 19.5, and 35.2 mg/g, respectively. The developed method was successfully applied to food samples to determine analyte concentrations. (C) 2016 Published by Elsevier Ltd.
Synthesis and biological properties of axially bis − (3,4,5-trimethoxybenzyloxy) phthalocyaninato silicon (IV)
(Elsevier Science Sa, 2024) Dündar, Abdurrahman; Ozdemir, Sadin; Dundar, Abdurrahman; Agirtas, Mehmet Salih
In this study, bis(3,4,5-trimethoxybenzyloxy) phthalocyaninato silicon (IV) was obtained from the reaction of 3,4,5-trimethoxybenzyl alcohol with SiPcCl 2 . This phthalocyanine was characterized using 1 H NMR, FTIR, UV - vis and mass spectra. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, antidiabetic, deoxyribonucleic acid (DNA) cutting, biofilm inhibition, anti -microbial and antimicrobial photodynamic therapy (aPDT) activities of newly synthesized bis(3,4,5-trimethoxybenzyloxy) phthalocyaninato silicon (IV) molecule were studied. The best activities were 41.58 % at 100 mg/L for antioxidant and 41.66 % for antidiabetic at 400 mg/L concentration. The molecule degraded the biofilm matrix formed by Pseudomonas aeruginosa and Staphylococcus aureus as 78.61 % and 89.26 %, at 50 mg/L concentration, respectively. It was observed that E. coli , which was used as a model microorganism, was inhibited at a level close to 100 % even at the lowest concentration of 50 mg/L. While double strand break was observed at 50 mg/L DNA cutting activity, it was determined that DNA was reduced to nucleotides at 100 and 200 mg/L. The Pc also displayed effective antimicrobial and aPDT abilities against pathogens. With the application of aPDT, the effectiveness of antimicrobial activity increased 2 to 4 times. These increase rates are very important. The main conclusion of the study was that the newly synthesized compound exhibited various effective biological activities such as effective antioxidant, antidiabetic, DNA cleavage, antimicrobial, aPDT, biofilm inhibition and microbial cell viability inhibition.
Synthesis and characterization of novel magnetic nano-catalyst (Fe3O4@SiO2@EDDHA-Fe) and their hydrogen production activity
(Elsevier Sci Ltd, 2024) Umaz, Adil
Due to irreparable crises for nature and people, replacing fossil fuel -based energy with green energy sources is a necessity for nature and humanity. Hydrogen is considered a clean energy transport due to its high energy density, environmental friendliness, high efficiency, and recyclable nature. This study generated hydrogen through NaBH 4 ethanolysis. In hydrogen production studies, there are very few studies with magnetic nano catalysts and very few studies with cheap transition metals. In order to contribute to the literature in this field, in this study, Fe 3 O 4 @SiO 2 @EDDHA-Fe was produced for the first time and used in hydrogen production studies. Fe 3 O 4 @SiO 2 @EDDHA-Fe synthesis was successfully carried out and hydrogen production was successfully implemented. The study also utilized FT-IR, XRD, VSM, BET, and SEM-EDX methods to characterize the structural, physical, and chemical properties of MNCs. The average particle diameter and magnetization value of Fe 3 O 4 @SiO 2 @EDDHA-Fe were 12.81 nm and 30.6 emu/g, respectively. The catalysis experiment designed with 50 mg Fe 3 O 4 @SiO 2 @EDDHA-Fe and 93.75 mM NaBH 4 generated 840 mL H 2 /g NaBH 4 298 K and 947 mL H 2 /g NaBH 4 318 K in 5 -min duration, respectively. At room temperature, the hydrogen generation rate (HGR) and activation energy (Ea) of Fe 3 O 4 @SiO 2 @EDDHA-Fe reaction were calculated as 1040 mL H 2 /gcat & sdot; min and 5.39 kJ/mol, respectively. After the sixth cycle, the reusability test of Fe 3 O 4 @SiO 2 @EDDHA-Fe reaction still retained approximately 87% of the initial hydrogen production volume. The study concluded that Fe 3 O 4 @SiO 2 @EDDHA- Fe is a promising catalyst in hydrogen production from NaBH 4 ethanolysis, as it is affordable and easy to prepare compared to other expensive catalysts.
Synthesis of novel magnetic nano-sorbent functionalized with N-methyl-D-glucamine by click chemistry and removal of boron with magnetic separation method
(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2018) Tural, Servet; Ece, Mehmet Sakir; Tural, Bilsen
Click chemistry refers to a group of reactions that are fast, simple to use, easy to purify, versatile, regiospecific, and give high product yields. Therefore, a novel, efficient magnetic nano-sorbent based on N-methyl-D-glucamine attached to magnetic nanoparticles was prepared using click coupling method. Its boron sorption capacity was compared with N-methyl-D-glucamine direct attached nano-sorbent. The characterization of the magnetic sorbents was investigated by several techniques such as X-ray diffraction, scanning electron microscope, transmission electron microscope, dynamic light scattering, thermogravimetric analysis, Fourier transform infrared spectrophotometer, and vibrating sample magnetometer. The boron sorption capacity of sorbents was compared by studying various essential factors influencing the sorption, like sorbate concentration, sorbents dosage, pH of the solution, and contact time. Langmuir and Freundlich and Dubinin-Radushkevich adsorption isotherms models were applied. Percent removal and sorption capacities efficiencies of sorbents obtained with direct and click coupling are found to be 49.5%, 98.7% and 6.68 mg/g, 13.44 mg/g respectively. Both sorbents have been found to be compatible with Langmuir isotherm, and the boron sorption kinetics conforms to the pseudo second order kinetics. The reusability study of sorbents was carried out five times for boron sorption and desorption.
Thermophilic Geobacillus galactosidasius sp nov loaded gamma-Fe2O3 magnetic nanoparticle for the preconcentrations of Pb and Cd
(ELSEVIER SCI LTD, 2016) Ozdemir, Sadin; Kilinc, Ersin; Okumus, Veysi; Poli, Annarita; Nicolaus, Barbara; Romano, Ida
Thermophilic bacteria, Geobacillus galactosidasius sp nov. was loaded on gamma-Fe2O3 magnetic nanoparticle for the preconcentrations of Pb and Cd by solid phase extraction before ICP-OES. pH and flow rate of the solution, amounts of biosorbent and magnetic nanoparticle, volume of sample solution, effects of the possible interferic ions were investigated in details. Linear calibration curves were constructed in the concentration ranges of 1.0-60 ng mL (1) for Pb and Cd. The RSDs of the method were lower than 2.8% for Pb and 3.8% for Cd. Certified and standard reference samples of fortified water, wastewater, poplar leaves, and simulated fresh water were used to accurate the method. LOD values were found as 0.07 and 0.06 ng mL (1) respectively for Pb and Cd. The biosorption capacities were found as 34.3 mg g (1) for Pb and 37.1 mg g (1) for Cd. Pb and Cd concentrations in foods were determined. Surface microstructure was investigated by SEM-EDX. (C) 2015 Elsevier Ltd. All rights reserved.
Tolerance and bioaccumulation of U(VI) by Bacillus mojavensis and its solid phase preconcentration by Bacillus mojavensis immobilized multiwalled carbon nanotube
(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2017) Ozdemir, Sadin; Oduncu, M. Kadir; Kilinc, Ersin; Soylak, Mustafa
In this study, uranium(VI) tolerance and bioaccumulation were investigated by using thermo-tolerant Bacillus mojavensis. The level of U(VI) was measured by UV-VIS spectrophotometry. The minimum inhibition concentration (MIC) value of U(VI) was experimented. Bacterial growth was not affected in the presence of 1.0 and 2.5 mg/L U(VI) at 36 h and the growth was partially affected in the presence of 5 mg/L U(VI) at 24 h. What was obtained from this study is that there was diversity in the various periods of the growth phases of metal bioaccumulation capacity, which was shown by B. mojavensis. The maximum bioaccumulation capacities were found to be 12.8, 22.7, and 48.2 mg/g dried bacteria, at 24th hours at concentration of 1.0, 2.5 and 5 mg/L U(VI), respectively. In addition to these, U(VI) has been pre-concentrated on B. mojavensis immobilized MWCNT. Several factors such as pH, flow rate of solution, amount of biosorbent and support materials, eluent type, concentration and volume, the matrix interference effect on retention have been studied, and extraction conditions were optimized. Preconcentration factor was achieved as 60. Under the optimized conditions, the limit of detection (LOD) and quantification (LOQ) were calculated as 0.74 and 2.47 mu g/L. The biosorption capacity of immobilized B. mojavensis was calculated for U(VI) as 25.8 mg/g. The results demonstrated that the immobilized biosorbent column could be reused at least 30 cycles of biosorption and desorption with the higher than 95% recovery. FT-IR and SEM analysis were performed to understand the surface properties of B. mojavensis. (C) 2016 Elsevier Ltd. All rights reserved.

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